Field of the Invention
The present invention relates to a control device, an actuator including the control device, an image blur correction device, an interchangeable lens, an image pickup apparatus, and an automatic stage. More specifically, the present invention relates to a control device that compensates individual differences of driving forces of a plurality of motors by learning, and synthesizes the driving forces of the motors, thereby allowing a moving body to move in multiple directions, an actuator including the control device, an image blur correction device, an interchangeable lens, an image pickup apparatus, and an automatic stage.
Description of the Related Art
Conventionally, among actuators capable of driving multiple directions (hereinafter, called a multi-degree-of-freedom drive device), a device that achieves XYθ driving using a linear actuator has been proposed (Japanese Patent Application Laid-Open No. 2009-225503).
FIG. 20A is a diagram illustrating a configuration of a conventional multi-degree-of-freedom drive device. The diagram illustrates a base plate 1, which is a base of the multi-degree-of-freedom drive device, and vibrators 2, 3 and 4 that drive a moving body 5. The diagram also illustrates a position sensor 6 that detects a position in an X direction. The diagram further illustrates position sensors 7 and 8 that detect positions in a Y direction.
FIG. 20B is a side view of the apparatus. The vibrators 2 (not illustrated), 3 and 4, into which vibrating members (top of the vibrators 3 and 4) having one point projection and piezoelectric elements (hatched parts) are integrated by adhesion, are attached to the base plate 1 via attachment members, not illustrated. Scales 6′, 7′ and 8′ are provided on the top surfaces of the position sensors.
For example, when the scale 6′ moves in the X direction, the sensor 6 outputs a position signal in response to a movement amount.
When the scale 7′ and 8′ move in the Y direction, the sensors 7 and 8 output position signals in response to movement amount, respectively. This configuration moves the moving body in a direction into which the driving forces of the vibrators 2, 3 and 4 are vector-synthesized.
Unfortunately, the conventional configuration has a problem in that, if the driving forces of the vibrators 2, 3 and 4 have individual differences, a control system is unstable, control gains cannot be increased, and the positional deviations and responsiveness are reduced.
To solve this problem, there is a method that preliminarily grasps the characteristics of individual motors and selects motors having similar characteristics. However, even it the motors have the same characteristics, variation in state of being actually attached in apparatuses (e.g., pressurization) also causes the problem.
Japanese Patent Application Laid-Open No. 2009-225503 proposes a method that determines the characteristics of individual motors from a movement amount of a moving body or manipulated amount of vibrators in the case of operation in an apparatus state, and sets drive parameters so as to match the characteristics with each other or to optimize the characteristics, thereby accommodating variation in the motors.